Invalid walker



FIG. 1 is a rear elevation view of an invalid walker showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a side elevation view thereof, the opposite side elevation view being a mirror image of that shown;

FIG. 4 is a top plan view thereof;

FIG. 5 is a perspective view thereof. 

The ornamental design for an invalid walker, as shown and described. 